Question

when turmeric poder reacts with soap it turns red not other colors why?

Answer 1

because it is an natural indicator which change it colour in base as well as in acid when turmeric combines with any base it turns red when it came in contact with acid remain yellow

Answer 2

When turmeric comes in contact with soap , it reacts with the fatty acids present in the soap and hence the carotene pigment gets more active than the xanthophylls and turmeric turns red.